When “Don’t Know” Indicates Nonignorable Missingness: Using the Estimation of Political Knowledge as an Example

The conventional procedure for measuring political knowledge is treating nonresponses such as “don’t know” as incorrect responses and counting the number of “correct” responses. In recent times, increasing attention has been paid to partial knowledge hidden within incorrect and nonresponses. This article explores partial knowledge indicated by incorrect and nonresponses and considers nonresponses as nonignorable missingness. We propose a model that combines the shared-parameter approach presented in the literature on missing data mechanisms and the methods of item response theory. We show that the proposed model can determine whether the people with nonresponses should be treated as more or less knowledgeable and detect whether it is appropriate to pool nonresponses and incorrect responses into the same category. Furthermore, we find partial knowledge hidden within women’s nonresponses, which confirms the possibility of the exaggeration of the gender gap in political knowledge.

Assessing controls on organic matter enrichments in hemipelagic homogenous marls of the Cretaceous Vocontian Basin (France): an unexpected variability observed from multiple organic-rich levels

The Marnes Bleues Formation from the Vocontian Basin (Southeastern France) shows many organic rich levels, some concomitant to oceanic anoxic events OAE1a and OAE1b. These organic-rich levels are scattered through a thick homogeneous succession of marls, poor in organic matter (OM). Through a multi-parameter approach, the organic-rich levels from the Aptian-Albian were characterized. Our results show that all OM-rich levels exhibit variable characteristics, such as OM nature (marine vs. continental), sedimentation and accumulation rates, redox conditions, surface-water productivity and relative sea level, but they all show low to modest enrichments in OM. Furthermore, all the levels share in common the fact that they formed under conditions of normal to low productivity and oxic to suboxic conditions. Thus, our results strongly suggest that, in the absence of high productivity and anoxic bottom conditions, the other factors reputed to favor OM accumulation only led to sporadic and low enrichments in organic contents. It is as if such factors could only enhance OM accumulation but could not induce it alone. What was true for the Vocontian Basin may be extended to other settings, regardless of their time of deposition or location.

Computing the Number of Failures for Fuzzy Weibull Hazard Function

The number of failures plays an important factor in the study of maintenance strategy of a manufacturing system. In the real situation, this number is often affected by some uncertainties. Many of the uncertainties fall into the possibilistic uncertainty, which are different from the probabilistic uncertainty. This uncertainty is commonly modeled by applying the fuzzy theoretical framework. This paper aims to compute the number of failures for a system which has Weibull failure distribution with a fuzzy shape parameter. In this case two different approaches are used to calculate the number. In the first approach, the fuzziness membership of the shape parameter propagates to the number of failures so that they have exactly the same values of the membership. While in the second approach, the membership is computed through the α-cut or α-level of the shape parameter approach in the computation of the formula for the number of failures. Without loss of generality, we use the Triangular Fuzzy Number (TFN) for the Weibull shape parameter. We show that both methods have succeeded in computing the number of failures for the system under investigation. Both methods show that when we consider the function of the number of failures as a function of time then the uncertainty (the fuzziness) of the resulting number of failures becomes larger and larger as the time increases. By using the first method, the resulting number of failures has a TFN form. Meanwhile, the resulting number of failures from the second method does not necessarily have a TFN form, but a TFN-like form. Some comparisons between these two methods are presented using the Generalized Mean Value Defuzzification (GMVD) method. The results show that for certain weighting factor of the GMVD, the cores of these fuzzy numbers of failures are identical.

Pendugaan umur simpan metode extend storage studies dan pengaruh lama penyimpanan terhadap organoleptik simplisia Mentha x piperita L

Mentha x piperita L. simplicial may undergo deterioration during storage, therefore it is very important to determine its shelf life. The determination of shelf life was done using Extend Storage Studies (ESS) method. This study was aimed to determine the shelf life and the effect of storage time on organoleptic simplicia M. x piperita. The sample used was simplicia that has been stored for 0, 15, 22, 30, 32, and 44 mounth in the simplicia storage warehouse with some long storage, and then the samples were subjected for moisture content analysis and organoleptic evaluation. The results showed that the shelf life of M. x piperita simplisia determined using the method of a water content parameter approach was 27 months. After 27 months of storage, although the aroma still can be preserve, there wa a decrease in the taste and the color of simplisia. In addition, there was increase in water content.

Thermal Modelling and Analysis of A 10HP Induction Machine Using the Lumped Parameter Approach

The essence of this research work is to develop a thermal model for an induction machine that will enable the prediction of temperature in different parts of the machine. This is very important first to the manufacturer or designer of an induction machine because with these predictions one can decide on the insulation class limits the machine belongs to. Also modern trends in the construction of machines is moving in the direction of making machines with reduced weights, costs and increased efficiency. In order to achieve this, the thermal analysis becomes very crucial in deciding on what types of insulators and other materials that would be used to make these machines. In industries, the knowledge of the thermal limits of machines if well utilized increases the life span of the machines and reduces downtime; thereby increasing production and profit. Specifically, this paper (i) predicted the temperature limits of the induction machine and its components, (ii) developed an accurate thermal model for an induction machine, (iii) predicted the temperature in different parts of the induction machine using the thermal model and software program and lastly (iv) investigated how the machine symmetry is affected by the nodal configuration.